Possible tire size upgrade?

So I just finished my Lift kit, 2" brackets in the rear and 4" up front but I've been driving around leaning up until yesterday when I finally had time to take the rear end apart with my buddies. I really don't want to get rid of these rims as I've had them since the truck drove off the dealership I just hate the offset as it basically forces me to run spacers. Right now I am running 265/70R18 Cooper discoverer at3, they're around 48 pounds per tire, really heavy duty. If I am gonna be honest they have horribly I will never ever buy from cooper again for that reason. At this rate I will be buying new tires before the end of the year which sucks because my Michelins lasted near 3 years on my truck. Granted these are all terrains but I expected more from them considering I shelled out better near $900 for them. I'd like to go up in tire size while remaining around the same weight more or less, I don't tow so I probably shouldn't have gotten such heavy thick tires but live and learn LOL. Thanks for any input.

 

11.5" x 34.6" is about as large as you can go without the body chop mod and they will clear the UCA. Problem is, that size is usually more expensive than a 12.5" x 35" Spacers make turning clearance issues worse.

 

Yeah I've got JBA uca's I was looking into that because these rims are 8.5" wide I believe so I wasn't sure what 34.6" will fit on my rim don't have much experience with non metric sizes oddly enough, I'm running 2" spacers up front just to bring the wheels out to the body line without it the truck looks pretty weird on stock rims.